Safety chuck key



Oct. 30, 1945. l c. c. DAVIS 2,387,981

- SAFETY CHUCK KEY 'l Filed June 21, 1944 Patented Oct. 30, 1945 SAFETY CHUCK KEY Cecil C. Davis, Bristol, Tenn., assigner of onehalf to Frank J. Gobble, Bristol, Tenn.

Application June 21, 1944, Serial No. 541,411

V4I Claims.

This invention relates to a safety tool or` key for rotary chucks.

In rotary tools, such as rotary drills and the like, the tool is held by means of a chuck. The iaws of the chuck are retractable so that the tool may be removed. The retraction of the jaws of the chuck is normally obtained by rotation of a sleeve, which sleeve in turn imparts a camming action on the jaws. When a tool is withdrawn from the jaws of the chuck, and a new tool placed between the jaws, the normal procedure of tightening the jaws is to use a key which is inserted into a socket of the stationary portion of the chuck, the key having a suitable pinion gear thereon which meshes wth,a gear rack on the lower portion of the rotatable camming sleeve, thus rotating the sleeve relative to the chuck proper. If the workman or mechanic forgets to remove the key from the chuck, and the rotary power is transmitted to the chuck, the centrifusal action of the rotating chuck will throw the key outwardly. Such circumstances have in the past caused serious injury to workmen and have also caused considerable damage to the chuck.

The main object of this invention is to provide a combination of a rotary chuck and a key therefor` wherein the key will be automatically and forcibly ejected entirely away from the chuck after the key has been used to tighten or release the iaws of the chuck.

Another object of the invention is to provide such a combination mentioned above wherein the means for automatically ejecting the entire key from the chuck is housed entirely within the key.

Another object of the invention is to provide a combined chuck and' a key therefor, ,wherein the entire key will automatically be forcibly ejected away from the chuck after the key has been used in connection with the chuck, wherein the automatic means for so doing is housed entirely within the chuck.

Another object of the invention is to provide a safety key wherein, should the mechanic or workman fail `to remove the key from the chuck after inserting a new drill or the like within the chuck, the key will automaticallyrand forcibly eject itself so that it will be thrown outwardly from the chuck immediately after the key has been used and before the mechanic leaves his position to start the rotation of the chuck.

Another .object of the invention is to provide a safety key which is formed of relatively few simple parts which may be easily and cheaply made and assembled.

Qther objects will be apparent from the following specification and the accompanying drawmg.

In the drawing:

Figure 1 is a side elevational view of a rotal'l1 chuck and of the safety tool shown in operative engagement with the chuck.

Figure 2 isa sectional view of the safety key. partly in section;

While Figure 3 is 'a fragmentary sectional view showing a modification of the invention.

In the drawing, reference is made particularly to Figure 1 wherein I0 indicates the jaws of the chuck which are movable toward and away from each other by the knurled sleeve I2. Rotation of the sleeve I2 in one direction causes the jaws l0 to move toward,` each other so as to provide a suitable gripping action on a tool inserted between the jaws, while rotation in the other direction causes the jaws III to move away from each other, thereby permitting a tool inserted between the jaws to be retracted therefrom. The knurled sleeve I2 is provided with the usual gear rack I4 which gear rack is positioned on the under side of the sleeve I2. Reference numeral I6 indicates the portion of the chuck which is stationary relative to the sleeve I2. A` plurality of sockets I8 extend through a portion of the stationary member I6, all of which is well-known and customary in the art.

Reference numeral 20 generally indicates the safety key which forms the preferred form of the invention. The tool or key 20 is formed of a shank member 22 which is hollow and cylindrical so as to leave a cylindrical bore 24 therein. A reduced cylindrical bore 26 is formedintegrally of the forward end of the shankl 22 and provides a shoulder 2B between the bores 24 and 2G. The bore 26 is formed by a reduced shank member 3U. The usual pinion gear 32 is formed integrally between the Shanks 22 and 30, and is adapted to mesh with the rack gear 40 formed on the knurled sleeve I2.

A plunger a4 is adapted to fit within, and slide relative to, the bore 26, the plunger 34 having a cylindrical head 36 formed integrally with the plunger 34 on its inner end thereof. A suitable coil compression spring 38 is positioned within the bore 24 and one end of the coil spring `38 is adapted to bear againsty the head 26 of the plunger 34, while the other end of the coil spring 38 bears against, and is held within the bore 24, by means of a suitable handle 40 which is inserted through a suitable aperture 42 formed within the shank 22.

It should be noted that4 the forward end 0f the plunger 34 extends for a considerable distance beyond the end of the reduced shank 38, and is held in such position by means of the coil compression spring 38. When the tool or key is to be used in connection with the chuck, the plunger 34 is inserted within one of the sockets I8 of the chuck, and in order to provide a meshing engagement between the pinion gear 32 formed on the tool 28 and the rack gear I4 formed on the sleeve I2, sufiicient pressure must be exerted on the tool 20 to cause the plunger 34 to beretracted within the bore 24 against the tension of spring 38. When such pressure is exerted on the tool 20, the plunger assumes the position shown in dotted lines in Figure l. When the tool is properly positioned relative to the chuck, as shown in Figure 1, rotation of the handle 40 will cause the knurled sleeve I2 to rotate relative to the member I6, thus causing the jaws I to move toward or away from each other, depending upon the direction of rotation of the. tool.

After a new tool has been inserted between the l jaws I0, and the sleeve I2 rotated in the proper direction to cause the jaws to hold the tool firmly within the chuck, and the workman relieves the initial pressure of the key 28, the entire key will be forcibly thrown outwardly from the chuck by the spring 38 pushing the plunger 34 outwardly' from the tool, thereby forcing the bevel gear 32 from disengagement with the rack gear I4. The spring should be of sufiicient strength so that when the pressure on the tool is relieved, the spring and plunger act with a snap action to force the entire key away from the chuck. Thus, it will be obviousthat should the workman forget to remove the key from the chuck, the key will automatically act to remove itself from the chuck so that there would be no possibility of the key ever being left in the chuck to cause serious bodily injury and/or mechanical damage when the chuck is again rotated at high speeds.

The modification of the invention shown in Figure 3'utilizes the basic concept of the invention already described. In this modification, the socket formed within the stationary portion of the chuck I6 is considerably enlarged so as to house a coil compression spring 44. The socket I8 has an annular shoulder 46 at its outer end. Suitable disk 48 is positioned within the socket I8. `*One end of the spring 44 bears against the inner wall of the ,socket I8 while the other end of the spring. 44 bears against the inner side of the disk 48. The annular shoulder 46 retains y the assembly within the socket I8.

In the operation of the modification shown in Figure 3, the usual rigid key now commonly used in the industry is utilized. The end shank portion of the key is inserted against the disk 48 and, by exerting suitable pressure on the tool, the disk 48 is pushed inwardly against the tension of the spring 44 so that the usual bevel gear on the tool will mesh with the rack gear formed on they rotatable sleeve. Here again, should the workman forget to manually remove the usual key from the socket I8, the spring and disk assembly 44 and 48, respectively, will automatically force the entire key outwardly from the chuck. Here, again, the spring 44 should be of suflcient strength so that when the pressure on the key is relieved, the spring and disk act with a snap action to force the entire key away from the chuck.

I claim:

1. A safety key for chucks comprising, a first shank member, a rst cylindrical bore within said first shank member, a gear positioned on the outer periphery of said first shank member, a second shank member secured to said rst shank member and extending beyond said gear and adapted to seat within a socket of a chuck, a second cylindrical bore' within said second shank member, a plunger slidably mounted within said second bore, a compression spring housed within said rst bore having `one end thereof bearing against said plunger for normally maintaining a portion of said plunger beyond said second shank member and permitting said plunger to be retracted within eachof said bores when the key is used with the chuck 2. A safety key for chucks comprising, a first shank member, a rst cylindrical bore within said first shank member, a gear positioned on the outer periphery of said first shank member, a second shank member secured to said first shank member and extending 'beyond said gear and adapted to seat within a socket of a chuck, a second cylindrical bore within said second shank member, a plunger slidably mounted within said second bore, an aperture throughsaid rst shank member, a handle positioned within said aperture, a compression spring housed within said first bore having one end bearing against said plunger for normally maintaining a portion of said plunger beyond said second shank member, and the other end of said spring bearing against said handle, said spring permitting said plunger to be retracted within each of said bores when the key is used with a chuck.

3. A safety key for chucks comprising, a first shank member, a rst cylindrical bore within said first shank member, a gear positioned on the outer periphery of said first shanky member, a second shank member secured to said first shank member and extending beyond said gear and adapted to seat within a socket cfa chuck, a second cylindrical bore within said second shank member, a plunger slidably mounted within said second bore, an aperture through said rst shank member, a handle positioned within said aperture, means within said first bore for normally maintaining a portion of said plunger beyond said secon'd shank member and permitting said plunger to be retracted within each of said bores when the key is used with a chuck, and means including said handle for maintaining said flrst mentioned means within said first bore.

4. A safety key for chucks comprising, a first shank member, a rst cylindrical bore within said first shank member, a gear positioned on the outer periphery of said first shank member, a second shank member secured to said rst shank member and extending beyond said gear and adapted to seat within a socket of a chuck, a second cylindrical bore within said second shank member, a plunger slidably mounted within said second bore, a shoulder formed between said bores, an aperture through said first shank member, a handle positioned within said aperture, a compression spring housed within said rst bore having one end bearing against said plunger for normally maintaining a portion of said plunger beyond said second shank member and permitting said plungerj to be retracted within each of said bores when the key'eis used with a chuck, and means for maintaining said compression spring within said first bore including said shoulder and said handle. CECIL C. DAVIS. 

